1. Field of the Invention
The present invention relates to a fixing apparatus which is used in a picture-image formation apparatus, such as copiers, electrophotographic printers and electro-static recording printers, for fixing a visible picture image on a recording material.
2. Description of the Related Art
In an apparatus for fixing a non-fixed picture image, wide use has been made of a thermal roller fixing method where a recording material having a non-fixed toner image thereon is heated by a heating roller maintained at a given temperature and a pressing roller having an elastic layer that presses against the heating roller while the recording material is being grasped and transported. A belt fixing apparatus is also known which is disclosed in U.S. Pat. Nos. 3,578,797 and 4,755,849 and in Japanese Patent Unexamined No. 50-16936 and Japanese Patent Examined No. 57-41672.
However, such heat fixing apparatus have problems due to the lengthy warm-up time required before the heating body is raised to a specified temperature. Hence, there has been proposed in an earlier Serial No. 206,767, assigned to the assignee of the present invention, a fixing apparatus in which the warm-up time is considerably reduced or eliminated by the use of a fixed heating body and a thin film. This fixing apparatus has excellent thermal response from the heating body since a thin film is not disposed between the heating body and the recording material. However, the thermal capacity is slightly larger by as much as the thin film.